canvas画板
1.只有画线功能的画板
<!DOCTYPE html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<style type="text/css">
#canvas{ border:2px dashed #0000FF;}
</style>
</head>
<body onkeydown="test()">
<canvas width="600" height="400" id="canvas"></canvas>
<script type="text/javascript">
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
ctx.lineWidth = 3;
ctx.strokeStyle = "red";
var paint = 0;
canvas.onmousedown = function(e){
var mouseX = e.pageX - this.offsetLeft;
var mouseY = e.pageY - this.offsetTop;
paint = 1;
ctx.moveTo(mouseX,mouseY);
}
canvas.onmouseup = function(e){
paint = 0;
}
canvas.onmousemove = function(e){
var mouseX = e.pageX - this.offsetLeft;
var mouseY = e.pageY - this.offsetTop;
if(paint){
ctx.lineTo(mouseX,mouseY);
ctx.stroke();
}
}
</script>
</body>
</html>
效果图
